In Portugal like in many other countries we can find statistics in the mathematics curriculum, and statistics is taught in mathematics classes by mathematics teachers until university level. During the compulsory levels most Portuguese students learn statistics in a traditional way. In this paper, we analyse dialogues of 7th grade students during collaborative work. The main objective was to understand some benefits of this kind of work on students' statistical reasoning. Our results suggest that collaborative work improve students' statistical reasoning as a result of the discussions and clarifications of their ideas and resolutions but also shows that this kind of work plays an important role in supporting students' development of positive orientations towards statistics.